[Ti] utility for defragmenting my internal HD?

[Mark C. Langston]

On Fri, Dec 20, 2002 at 11:01:54AM -0800, Bill Reburn wrote:
> I don't understand what you and Loren are talking about.
> 
> I see you using the word 'should' - making me think this is a guess?
> If anyone has opened up DiskWarrior or Norton on an OSX disk - they will see
> that after only an initial installation of OSX and some applications that
> Hard Drive fragmentation is quite apparent. Stuff gets thrown form here to
> there.
> 
> After some months of use - the fragmentation is just as light or severe as
> OS9 had - all depends on usage.
> 
> Or at least that is what is happening on my end.. Are these applications
> incorrectly reporting these results? I can see OSX being able to handle
> whatever is thrown at it.. But there are absolute performance differences on
> machines (HD's) that have been severely fragmented.
> 

Your applications are displaying the data accurately.
What they're saying is this:  The filesystem that OS X uses is different 
than that used by OS 9, or Windows.  It's derived -- as is almost every
other Unix filesystem -- from Kirk McKusik's Berkeley Fast Filesystem
(BFFS).  This type of filesystem was designed to handle fragmentation
well instead of poorly.

In other words, yes, your filesystem is fragmented.  However, on OS X,
it doesn't matter.  The way the filesystem goes from one block to the
next (rather, from one inode to the next) doesn't depend upon the
location of the next inode, from a logical point of view (there will
be a miniscule impact should the data be on a significantly different
physical portion of the disk, but a) you wouldn't notice it, and
b) it's more a factor of the hard drive spindle speed and head seek time
than it is of fragmentation).

So relax, and ignore those fragmentation reports.  Or revel in the fact
that you don't need to defragment any more.  It's just another benefit
of using a Unix-based OS.


-- 
Mark C. Langston                                    Sr. Unix SysAdmin
mark at bitshift.org                                       mark at seti.org
Systems & Network Admin                                SETI Institute
http://bitshift.org                               http://www.seti.org